The long-term goals of this project is the development of technology (such as microsensor arrays, automatic calibration, pattern recognition methods) to allow the design of portable, inexpensive, and reliable instruments with exceptional analytical capabilities for the measurement of blood alcohol levels (non-invasive). Other important chemical sensing problems may be addressed with the proposed approach in medical, health science, environmental, and industrial markets. The proposed work seeks to integrate recent advances in dynamic coulometry with new capabilities in computerized portable instrumentation to improve analytical performance (better selectivity and sensitivity) with better logistics for field use (i.e. easier to use with auto-test and calibrate functions as well as smaller size and lower cost for practical field delopment to a large number of users).